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Re: mutexes, IPL, tty locking

On Tue, Nov 03, 2009 at 07:26:25PM +0900, Masao Uebayashi wrote:
> What if one thread is about to
> access PCI.  Unplug interrupt happens, you execute detach process in IPL_HIGH
> interrupt.  Now back to the original thread, it just accesses PCI and you
> lose...

There is a window of time where accesses "in flight" (for example,
posted writes) or an instruction sequence in progress will generate
exceptions.  I plan to deal with those exceptions.  To keep the window
of time manageable, I will service PCI exceptions and device-detachment
notifications at a high priority.


David Young             OJC Technologies      Urbana, IL * (217) 278-3933

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